typescript-union

0.2.0 verified Mon Apr 27 auth: no javascript deprecated

A utility library providing generic types for manipulating TypeScript unions at the type level. Version 0.2.0 is current; the package is experimental and sees infrequent updates. Key differentiators: offers type transformations such as filtering and mapping union members without runtime code. Alternatives like type-fest or utility-types provide broader type utilities but may lack union-specific operations.

Common errors

error Cannot find module 'typescript-union' or its corresponding type declarations. ↓

cause Package not installed or missing type definitions.

fix

Install: npm install typescript-union --save-dev

error 'Filter' cannot be used as a value because it is a type. ↓

cause Runtime usage of a type-only export.

fix

Remove from runtime code or use import type.

Warnings

deprecated Package is abandoned; no updates since 2020. ↓

fix Consider alternatives like type-fest or ts-essentials.

gotcha All exports are types only; importing at runtime will cause errors. ↓

fix Use import type syntax: import type { Filter } from 'typescript-union'.

breaking Removal of deprecated type aliases in version 0.2.0. ↓

fix Replace deprecated aliases with the new names per changelog.

Install

npm install typescript-union

yarn add typescript-union

pnpm add typescript-union

Imports

Filter
```
import { Filter } from 'typescript-union'
```
Used in type context only; no runtime export.

Split

wrong

const { Split } = require('typescript-union')

correct

import { Split } from 'typescript-union'

ESM-only; avoid CommonJS require.

UnionToIntersection

import { UnionToIntersection } from 'typescript-union'

Exported as named type.

Quickstart

Demonstrates Filter and UnionToIntersection type utilities for union transformations.

import { Filter, UnionToIntersection } from 'typescript-union';

type Mixed = string | number | boolean;
type OnlyStrings = Filter<Mixed, string>; // string

type Funcs = ((x: string) => void) | ((x: number) => void);
type Intersected = UnionToIntersection<Funcs>; // (x: string & number) => void